Retrievable stabilizer for well bores



Jan. 2o, 1959 IMI DE'ORR COOK' RETRIEVABL STABILIZER FORv WELL. BORES vFilled June 11, 195e` IN1/EN TOR. @E Oe/2 600K BV, JMU

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2,869,827 RETRIEVABLE STABILIZER FOR WELL BoRES DeOrr Cook, Ventura, Calif. Application Jane 11, 1956, serial No. 590,649 ,6 Claims. (C1. 255km) This invention relates to a well-boringtool and particularly to a stabilizer or reamer that operates in a drilling string above the bit at the end of the string. This application is a continuation-impart of my pending application bearing the same title, Serial No. 398,147, filed December 14, 1953, andnow abandoned.

In a rotary well drilling, it is necessary, from time to time, to withdraw the drilling string-for various reasons, among which is replacement or repair of the drilling tool orbit. Frequently, and especially in deeper holes, the lateral whip in a drilling string, several hundred or even thousands of feet long, will form a seatin the side of the well bore that, in most cases, is smaller in diameter than the bit. In such case, the bit may become wedged the seat and prevent further retraction of the string. lf reamers are used above the bit, the same may also become wedged. Thereare also instances when, because of faults in the formation being drilled, the sides of the bore collapse around the drill string and form a barrier to progress of the drill string to the surface.` The foregoing suggest some of the ways that obstruct upward retraction of a drill string and, unless these obstructions :are removed or enlarged, great diicultyis encountered in retrieving that portion of the string that becomes wedged or jammed; Abandonment of: thek bore may result, with great economic loss.` n

Accordingly, it is an object ot the present invention to provide a tool that can be withdrawn past an obstruc-,

tion in a well bore to enable retrieving of expensive equipmentand retain the bore in condition for further drilling.

Another'object of the invention is to provide a tool of the character indicated` that enables use of both jarring force and rotational or torsion force tol etfect piercing-of a barrier to enable withdrawal of a drill)y stringy and subsequent recapture of the drill bit thereof.

The invention also has for its, objects to provide such means that are positive in operation, convenient in use, easily installed in a working position and easily. disconnected therefrom, economical of manufacture, relatively simple, and of general superiority and serviceability.

The invention also comprises novel details of construction and novel combinations and arrangementsof parts, which will more fully appear in the` course of the following description. However, the drawing merely shows and the following` description merely describes one embodiment of the present invention, which is given by way of illustration or example only. y

In the drawing, like reference characters designate similar parts in the several views.-

Fig. l is an elevational View, in quarter section, of a preferred form of retrievable tool according to the present invention and shown in its condition of normal use.

Fig.v 2 is a similar view showing said tool. separated from the bit-carrying end of a drill string and the condition thereof when used to pierce a barrier ina well bore.

Figs. 3 and 4 are cross-sectional views as taken on lines 3--3 and 4 4, respectively of Fig. l.

In the drawing, the vmember 5 represents lthe lower endv ice E of a drill string, the same-having a threaded pin 6, and the member 7 represents a drill collar that conventionally mountsa drill bit. The same has a threaded box 8. Member 7 also serves .to rep-resent a drill string above the drill collar should it be desired to space the bit some distance below member 7. The present tool 9 connects members 5 and 7 and, thereby, becomes a component of the drill string. it will be clear from the foregoing that tool 9 may be attached directly to a drill collar or may be connected to said collar by :an interposed length of-,drill rods, as desired.

The present tool 9 comprises, generally,- a mandrel 10 having an upper threaded box 11. that receives pin 6 of the string 5, a reaming collar 12 mounted on the mandrel itl and rotationally connected to the lower portion t3 ot said mandrel and in longitudinally sliding., engagement with said portion` 13, clutch means 14 adapted to interconnect the mandrel l and the reaming'collar 12 to effect a rotationalrdrive of the latter by the former, an extension piece l separably connected to and forming a lower extension ofthe mandrel it), and clutch means i 16 interconnecting the lower end of the reamingV collar yl2 and said extension piece 15,. said extension piece 15 being provided with a lower threaded pin that enters box 8- of the member 7 and, therefore, connects the present tool 9 with a drill collar or to the string above such collar,

as the case may be'. l

As shown, the reduced lower portion i3 of the mandrel l@ defines a downwardly-facing shoulder 17. Said end 13 is preferablyl of circular cross-section and the lower end thereof is shown as provided with an internally threaded box 1S. Said mandrel l0 is provided with a central longitudinal passage 19, the same being aligned with a similar passage 2@ in the drill string. Said aligned passages are used to downwardly conduct uid such as may be required in connection with the formation-drilling function of the bit on the end of the drill collar 7.

The reaming collar l2 is shown as a collar 21 that, as above explained, is rotationally fitted over', the reduced portion i3 of the mandrel. VSaid collar is provided with generally conventional reaming tins 22 that, during the normal use of the tool when in assembly as in Fig. l, rearn the walls of abore that is formed by the bit at the lower end of the st-ring.` inasmuch as the fins 212 are above the bit, and they may be provided a substantial distance thereabove, the same have a piloting engagement in the bore and this engagement serves toy stabilize the string against undue lateral whip. The collary Z1 is made of such length that its lower` end extends below the lowermost end of the mandrel 1t), even when said collar is retracted upwardly against shoulder 17. y

lt will be noted that between reduced end 13 and shoulder 17, the mandrel is further reduced at 23. ln said reduced portionk Z3-there is rotationally and slidingly fitted a fianged ring M that is in threaded connection, at 25 with theinternally threaded upper end ofthe reaming collar 2l.v Since said ring 242 fits reduced portion 25, the same is retained captive on the mandrel lll although being rotational relative to the mandrel and capable, of sliding movement between shoulder 17 andan upwardlyfacing shoulder 26 on the mandrel end 13, Ring 24 may be initially split and, after assembly around the mandrel portion 23, the two halves thereof may be brazed or welded together. The collar l2 partakes of all movements of ring 24 and, in addition, may be` disconnected from the ring by separation of the threaded connection 25.

rhe clutch means 14 is shown as preferably rectilinear teeth 27 extending upwardly from the mentioned.' shoulder 26, and similar interfitting downwardly directed teeth 28 on the lower portion of ring 24; It will beclear. that when the clutch teeth 27 and-28v are` intertted, as in Fig'. 2, the reaming collar 12 is rotationally locked,y witht the mandrel. When the clutch teeth are vertically separated, the mentioned relative rotation of mandrel and reaming collar is restored.

The extension piece 15 has its upper end 29 reduced to the dlametral size of the mandrel portion 13 so as to fit wlthin the collar 21. Said end 29 is provided with a threaded pin 30 lto enter box 18 of the mandrel. Said extenslon piece is also provided with a fluid-conducting passage 31 that constitutes a continuation of the passages 19 and 20.

From the foregoing it will be clear that mandrel 16 and extension piece 15, when joined as in Fig. l, constitute the body of the present tool, the reaming collar 12 being mounted on said body, and the same constituting a longitudinally separable two-part body.

The clutch 16 is shown as comprising clutch teeth 32 formed on the lower end of the reaming collar 21, and

interfitting clutch teeth 33 provided on a ring collar 34 connected by threads 34 to extension piece 15 between the main portion of said piece and the reduced upper end 29 thereof.

All threads on the tool are right hand threads as also are the threads of the pin and box connections with the drill string and the drill collar or bit.

During normal rotary drilling, the reaming fins 22 engage the wall of the bore and, while stabilizing the string, ream the bore that is formed by the bit at the end of the string. The sleeve 21, on which the fins are provided, is rotated with the string by the clutch means 16. Also, in this normal drilling position, the collar has little or no endwise movement relative to the mandrel 10 because the same is confined, at one end, by shoulder 17 of the mandrel and, at the opposite end, by the clutch means 16.

Since the threaded connection 35 is a right hand thread, the normal clockwise (from above) drilling rotation will produce a clockwise rotation on the mandrel extension 15. During its normal reaming function, clockwise direction of the reaming collar 12 is resisted by the engagement of the fins 22 with the bore wall. Consequently, because of the clutch connection between the collar 22 and the ring 34, the latter will run up on its thread 35. However, this rotation of ring 34 is stopped, after only a small movement, when the ring 24 is arrested by shoulder 17. Normal rotary drilling may continue with the parts in this condition.

Since the ns 22 are the largest diametrally-sized partsv of the tool, the same will encounter any obstruction there may be in the bore during withdrawal of the drill string. If the upward movement of the string is thus arrested by the seizure or wedging of the collar 12, the normal drilling direction of rotation of the string is reversed by application to the upper end of the string of a torque opposite to that used during the drilling operation. Since the collar 12 is tightly wedged and held against longitudinal as well as rotational movement, the clutch ring 34, by reason of the clutch means 16, is also held against rotation. Therefore, because of the threaded connection, at 35, between clutch ring 34 and mandrel extension 15, the latter is also held against rotation.

Thus, upon application of reverse torque on the string 5 and upon a suitable build-up of torsional force as the string is wound in a counter-clockwise direction, the pin and boX joint 30-18 will unthread. It is this joint that breaks rather than the pin and box joint 6-11 first, because -it is a smaller joint with less friction and, second, because the mandrel 10 is free to turn with the string 5, whereas the extension is locked against turning, as above described.

When the tool joint is broken, as above, the extension piece 15 and all parts suspended therefrom may drop back tothe bottom of the bore. The reaming collar 12 is now released from clutching engagement with the eX- tension piece 15, as shown in Fig. 2. Since the collar 12 remains wedged in the bore, in order to free the same, the drill string 15 is used as a ramming means by moving ag. the entire string up and down to effect longitudinal dislodgrnent of the collar from whatever obstructions in which it had become wedged. The opposed shoulders or abutments 17 and 26 alternately ram or jar against the ring 24 to effect such dislodgement.

Whereas, in the normal drilling position of the tool (Fig. 1), the clutch means 14 is inoperative because the teeth 27 and 28 thereof are kept longitudinally separated, when the tool is broken as in Fig. 2, said teeth 27 and 28 may interfit, as shown, when the string is pulled in an upward direction relative to the wedged reaming collar. Thus, by applying a clockwise torque to the string 15 while the same is being reciprocated to carry out the jarring function, said torque becomes effective, when the clutch teeth 27 and 28 engage, on the reaming collar to cause the same to have both a longitudinal and a rotational movement, the same cooperating to quickly release the collar from its seizing environment.

After the collar 12 has been released to enable complete withdrawal of the string from the bore, conventional fishing tools may be used to grip the extension 15to effect withdrawal of the same and the elements carried thereby. This withdrawal of the drill collar and blt is easily accomplished because the bore is now free of obstructions since the same has been pierced by the reaming collar.

While the foregoing has illustrated and descrlbed what is now contemplated to be the best mode of carrylng out the invention, the construction is, of course., subject to modification without departing from the spirit and scope of invention. It is, therefore, not desired to restrlct the invention to the particular form of construction illustrated and described, but to cover all modifications that may fall within the scope of the appended claims.

Having thus described my invention, what I clalm and desire to secure by Letters Patent is:

1. A stabilizer interconnecting upper and lower parts of a drill string comprising a mandrel adapted to be engaged with the upper part of said drill string, a. tubular extension piece in threaded engagement w1th sald mandrel and adapted to be engaged with the lower part of said drill string, the lower end of said'mandrel and the upper end of said extension piece having a reduced diameter, a first collar having a plurality of reaming fins on the circumference thereof, said collar being engaged with the reduced portions of said mandrel and said extension piece and adapted to rotate thereon, a second coll'ar 1n threaded engagement with said extension piece, lnterengaging clutch means provided on adjacent ends of said collars to connect the collars to rotate together relative to the mandrel, and a shoulder on the mandrel to arrest retractive movement of the first collarl during rotation of the second collar on the threads connecting the same with the extension piece when the mandrel and extension piece are in threaded engagement and, thereby, retain engagement of the mentioned clutch means to hold the first collar non-rotational on the mandrel and extension piece during drilling rotation of the string, said first collar being mounted to be longitudinally slidable on said mandrel when said extension piece is disengaged, and stop means between the mandrel and first collar to limit sliding movement of said collar on said mandrel.

2. A stabilizer according to claim 1 in which the stop means comprises a ring having an abutment and is connected to the first collar, and an abutment shoulder on the mandrel and opposed to the mentioned shoulder, the ring being disposed between said shoulders.

3. A stabilizer interconnecting upper and lower parts of a drill string comprising a mandrel adapted to be engaged with the upper part of said drill string, a tubular extension piece in threaded engagement with said mandrel and adapted to be engaged with the lower part of said drill string, the lower end of said mandrel and the upper end of said extension piece having a reduced diameter, a first collar having a plurality of reaming ns on '5 the circumference thereof, said collar being engaged with the reduced portions of said mandrel and said extension piece and adapted to rotate thereon, a second collar in threaded engagement with said extension piece, interengaging clutch means provided on adjacent ends of said collars to connect the collars to rotate together relative to the mandrel, a shoulder on the mandrel to arrest retractive movement of the irst collar during rotation of the second collar on the threads connecting the same with the extension piece when the' mandrel and the extension piece are in threaded engagement and, thereby, retain interengagement of the mentioned clutch means to hold the rst collar non-rotational on the mandrel and extension piece during drilling rotation of the string, and a second clutch rotationally connecting the mandrel and the rst collar and normally separated when the mandrel and the extension piece are connected.

4. A stabilizer interconnecting upper and lower parts of adrill string comprising a mandrel adapted to be engaged with the upper part of said drill string, a tubular extension piece in threaded engagement with said mandrel and adapted to be engaged with the lower part of said drill string, the lower end of said mandrel and the upper end of said extension piece having a reduced diameter, a iirst collar having a plurality of reaming tins on the circumference thereof, said collar being engaged with the reduced portions of said mandrel andy said extension piece and adapted to rotate thereon, a Second collar in threaded engagement with said extension piece, interengaging clutch means provided on adjacent ends of said collars to connect the collars to rotate together relative to the mandrel, a shoulder on the mandrel to arrest retractive movement of the first collar during rotation of the second collar on the threads connecting the same with the extension piece when the mandrel and extension piece are in threaded engagement and, thereby, retain interengagement of the mentioned clutch means to hold the first collar non-rotational on the mandrel and eXtension piece during drilling rotation of the string, and a second clutch means provided on the rst collar and the mandrel and normally disengaged when the mandrel and the extension piece are connected, said second clutch means being effective to engage and provide a driving connection between the mandrel and the first collar upon longitudinal separation of the mandrel and the extension piece.

5. A tool of the characi'tr described comprising, in combination, a two-part mandrel provided with clutch teeth and with a rotational connection adapted to be separated upon rotation of one part relative to the other part, a reaming collar provided with clutch teeth and rotationally and slidingly connected to one part, opposed abutments on said one part to engage the collar and limit the sliding movement thereof relative to the mandrel, the clutch teeth being disconnected when the collar is at one limit of its position and connected to rotationally couple the mandrel and collar when the latter is at its other limit of position, a ring collar threadedly connected to the other mandrel part and provided with clutch teeth, and complementary clutch teeth on the reaming collar and engaged with the clutch teeth on the ring collar when the mandrel parts are connected to effect a rotational connection between said collar and the other mandrel part when the first-mentioned clutch teeth are disconnected.

6. A tool according to claim 5 in which the rotational connection of the two-part mandrel comprises a righthand thread, the threaded connection between the ring collar and the mandrel comprises a right-hand thread, the length of the mandrel between the abutment that limits the sliding movement of the reaming collar to said first limit of its position and the clutch teeth on the ring collar being greater than the length of the reaming collar, whereby, when the complementary :clutch teeth on the ring collar and the reaming collar are engaged, there is a longitudinal space between the opposite end of the reaming collar and the abutment that limits the sliding movement of the reaming collar to the first limit of its position, said ring collar running up on its right-hand thread to move the reaming collar longitudinally toward and against the last-mentioned abutment during application of a clockwise torque from above on the mandrel while the reaming collar is being held non-rotational.

References Cited in the tile of this patent UNITED STATES PATENTS 2,572,307 Brown et al. Oct. 23, 1951 2,620,164 Burris Dec. 2, 1952 2,665,887 Shelton Jan. 12, 1954 

